Continuous process of manufacture of cast iron or steel, by reduction of the iron ore

摘要

Cast iron or steel is produced from an iron ore or oxide by introducing natural gas or methane with the iron ore or oxide, preferably powdered and suspended therein, directly into a bath of molten iron containing dissolved carbon, e.g. cast iron or steel with 2-4% carbon at 1200-1300 DEG C., below the molten slag layer, e.g. 10 to 100 cms. below the molten iron surface, and burning the escaping reducing gases H2 and CO by means of oxygen introduced above the surface of the molten iron, preferably air supplied at the top surface of the slag. The quantity of natural gas or methane is at least sufficient to supply to the molten iron the amount of carbon being consumed in the ore reduction, i.e. one molecule of CH4 per atom of O combined with Fe. A slag of sufficient thickness may be formed by the reaction of impurities in the ore with a flux, or if pure iron oxide is processed, by adding one or more easily melting ores. The slag and cast iron or steel may be withdrawn continuously or intermittently. Any unburnt CO and H2 gases may be used in a prereduction stage.